
    html,
    body {
        height: 100%;
    }

    body {
        margin: 0;
        display: flex;
        align-items: center;
        justify-content: center;
        background-size: cover;
    }

    header {
        position: absolute;
        top: 0;
        width: 100%;
        height: 35px;
        z-index:1;
    }

    header ul {
        margin: 0;
        position: absolute;
        left: 0;
    }

    header li {
        display: inline-block;
        line-height: 35px;
        font-size: 13px;
        color: #ddd;
        margin: 0 18px;
        display: inline-block;
    }

    header li a {
        color: #ddd;
        text-decoration: none;
    }

    header li a:hover {
        color: #fff;
    }
    main{
        display: flex;
 position:absolute;
 align-items: center;
        top:120px;
        left:110px;
        z-index:1;
    }
    span{
        width:134px;
        height:53px;
        background-image:url(download.png);
    }
    input{
        width:540px;
        height:40px;
        font-size:25px;
    }
    button{
        height:46px;
        width:46px;
        border:8px solid #007daa;
        background-color:#007daa;
        background-image:url(download.png);
        background-position:-169px -61px;
    }

    footer {
        position: absolute;
        bottom: 0;
        width: 100%;
        height: 35px;
        background-color: #333;
        z-index:1;
    }

    footer ul {
        margin: 0;
        position: absolute;
        right: 10px;
    }

    footer li {
        display: inline-block;
        line-height: 35px;
        font-size: 13px;
        color: #666;
    }

    footer li a {
        color: #666;
        text-decoration: none;
    }
    footer li a:hover {
        color: #9a9a9a;
    }
    div{
        position: absolute;
        top:0;
        left:0;
        width:100%;
        height:100%;
        background-color:#000;
        opacity:0;
    }